1. Field of the Invention
The present invention relates to a projector-type vehicular headlamp.
2. Description of the Related Art
Projector-type headlamps have been employed as vehicular headlamps very often in recent years.
As shown in FIG. 7, the projector-type headlamp is equipped with a light source 102, a reflector 104, and a focusing lens 106. The light source 102 is substantially coaxially arranged with the optical axis Ax of a lamp, wherein the optical axis Ax extends in the longitudinal direction of a vehicle. The reflector 104 reflects light, from the light source, a little forward and toward the optical axis Ax of the lamp. The focusing lens 106 is provided in front of the reflector 104.
When the projector-type headlamp is used as a low-beam headlamp, a shielding plate 108xe2x80x94for shielding part of the light reflected from the reflector so as to remove the light emitted upwardxe2x80x94is provided between the focusing lens 106 and the reflector 104 as shown in FIG. 7. Thus, a low-beam light-distribution pattern having a predetermined cutoff line is formed by the light transmitted through the focusing lens 106.
3. Problems to be Solved by the Invention
As shown in FIG. 8(a), however, because the focusing lens 106 of such a projector-type headlamp 110 is generally formed with a single convex lens having a circular contour when viewed from the front of the lamp, the focusing lens only appears dimly lit when it is observed from the front of the lamp and, disadvantageously, the lamp looks unattractive.
Moreover, the projector-type headlamp is often incorporated in part of the lamp body 100 and, consequently, the contour of the lamp body 100 when viewed from the front of the lamp often looks substantially vertically rectangular. Thus, it is difficult to harmonize the designs of the lamp unit 110 and the lamp body 100.
Incidentally, U.S. Pat. No. 4,772,987 and U.S. Pat. No. 5,967,647 disclose arrangements for providing auxiliary reflectors for reflecting light from light sources forward without passing the light therefrom through focusing lenses. In these arrangements, however, the auxiliary reflectors are provided on the outer peripheral side of each reflector in a projector-type headlamp.
An object of the present invention, which has been made in view of the above-described problems, is to provide a projector-type headlamp having an improved external appearance when viewed from the front of the lamp, even when the projector-type headlamp is incorporated in a substantially vertically rectangular lamp body. Another object of the present invention is to improve design harmony between the lamp unit and the lamp body.
In order to accomplish the above and other objects, according to the present invention, predetermined auxiliary reflectors are respectively provided on both vertical sides of a reflector.
A projector-type vehicular headlamp includes:
a light source substantially coaxially arranged with an optical axis of the headlamp, wherein the optical axis extends in the longitudinal direction of a vehicle;
a reflector for reflecting light, from the light source, forward and towards the optical axis of the lamp;
a focusing lens provided in front of the reflector, so that a predetermined beam emission is made by using the transmission light of the focusing lens; and
a pair of auxiliary reflectors, for reflecting the light from the light source forward without passing the light therefrom through the focusing lens, respectively provided on both vertical sides of the reflector,
wherein on the whole, the contour of the pair of auxiliary reflectors, when viewed from the front of the lamp, looks vertically rectangular.
The above xe2x80x98light sourcexe2x80x99 is not limited to a specific kind but may be, for example, a filament of such as a halogen bulb, or a discharge light emitting portion of a discharge bulb.
The above xe2x80x98predetermined beam emissionxe2x80x99 is not limited to beam emission in a specific light-distribution pattern but may be, for example, beam emission in a low-beam light-distribution pattern, beam emission in a high-beam light-distribution pattern, beam emission to be made by selectively switching between the low-beam and high-beam light-distribution patterns, beam emission in a fog-lamp light-distribution pattern, and the like.
The above xe2x80x98pair of auxiliary reflectorsxe2x80x99 is not limited in specific configuration to any particular length and breadth ratio, surface configuration of the reflective surface of each reflector, and the like, as long as the auxiliary reflectors: are respectively provided on both vertical sides of the reflector; on the whole, the contour of the pair of auxiliary reflectors, when viewed from the front of the lamp, looks vertically rectangular; and are used for reflecting the light from the light source forward without passing the light therefrom through the focusing lens.
According to the above-described arrangement, the vehicular headlamp according to the invention is provided with a pair of auxiliary reflectors for forwardly reflecting the light from the light source without passing the light therefrom through the focusing lens. The auxiliary reflectors are respectively provided on both vertical sides of the reflector in the projector-type headlamp, and the contour of the whole of the pair of auxiliary reflectors, when viewed from the front of the lamp, looks vertically rectangular and longer than it is wide, so that the following operation and working effect are achievable.
In other words, when the projector-type headlamp being electrically turned-off is observed from the front side in ambient light, the presence of the reflective surfaces of the auxiliary reflectors on both vertical sides of the focusing lens therein makes the lamp look brighter on the whole in the vertically long, rectangular, form instead of making the focusing lens simply dimly lit by ambient light as before.
When the projector-type headlamp is incorporated in the whole lamp having a substantially rectangular contour, as viewed from the front thereof, there is avoided a feeling of wrongness in lamp design between the lamp unit and the whole lamp.
According to the invention, it is possible to improve the external appearance when observed from the front of the projector-type headlamp. Moreover, an improved design harmony between the lamp unit and the lamp body is possible.
Since the projector-type headlamp according to the invention is provided with the pair of auxiliary reflectors, there is prevented an increase in the lateral tilting angle between the reflective surfaces of the auxiliary reflectors, which increase occurs where the auxiliary reflectors are provided laterally respectively on both sides of the reflector. Therefore, according to the invention, the horizontal diffusion deflecting reflection control can be made by the auxiliary reflectors with greater precision.
According to the invention, the light reflected from the pair of auxiliary reflectors can be utilized for reinforcing the brightness of the light-distribution pattern formed by the light reflected from the reflector.
Also, a shielding plate for shielding part of the light reflected from the reflector so as to remove the light emitted upward is provided between the reflector and the focusing lens. Thus, in the projector-type headlamp formed to make the beam emission with the low-beam light-distribution pattern having a predetermined cutoff line formed by the shielding plate, it is possible to utilize the light reflected from the pair of auxiliary reflectors as the light for correcting the low-beam light-distribution pattern, irradiating the overhead sign and the like.
In that case, at least part of reflective areas of the pair of auxiliary reflectors is so arranged as to reflect the light from the light source toward the cutoff line with the following effect.
In the projector-type headlamp, the cutoff line of the low-beam light-distribution pattern has an extremely high brightness-to-darkness ratio. Consequently, for example, when the vehicle travels from a downward slope toward a flat road, the driver comes across a situation where he may hardly drive the car forward on the road surface because it has become suddenly dim, thus lowering visibility. Moreover, because of vertical pitching of the vehicle, and the like, the driver may give glaring light to an oncoming vehicle. Therefore, the light from the light source is reflected toward the cutoff line by utilizing the auxiliary reflectors thereby easing the brightness-to-darkness ratio so that it is easier for the driver to drive his/her own car with a low-beam light-distribution pattern that may give any on-coming vehicle driver a low-beam light-distribution pattern without glaring light.
Although the lateral breadth of each auxiliary reflector is not limited to any specific value, it can make the lamp appear rectangular, and substantially vertically longer when lit, thus improving the novel design of the lamp.
Alternatively, the contour of the focusing lens, when viewed from the front of the lamp, is obtainable by cutting out of the focusing lens both lateral end portions of a circle, and by setting the lateral breadth of each auxiliary reflector substantially equal in value to the lateral breadth of the focusing lens. When the lateral breadth of each auxiliary reflector is set smaller than that of the focusing lens, as when the focusing lens is allowed to stick out laterally beyond each auxiliary reflector, the lamp can appear rectangular and substantially vertically longer when lit by ambient light so as to improve the novel design of the lamp.
Although the reflective surface of each of the auxiliary reflectors is not limited to any specific form as described above, the substantially vertically long and rectangular configuration of the lamp can be strengthened further by forming the reflective surface with a plurality of dividing reflective elements.